Embodiments of the inventive concepts relate to three-dimensional (3D) semiconductor memory devices and, more particularly, to 3D semiconductor memory devices with improved reliability and integration density.
Semiconductor devices have been highly integrated to provide excellent performance and low manufacture costs. The integration density of semiconductor devices directly affects the costs of the semiconductor devices, thereby resulting in a demand of highly integrated semiconductor devices. The integration density of two-dimensional (2D) or planar semiconductor devices may be mainly determined by an area where a unit memory cell occupies. Therefore, the integration density of the 2D or planar semiconductor devices may be greatly affected by a technique of forming fine patterns. However, since relatively high-priced apparatuses are needed to form fine patterns, the integration density of 2D semiconductor devices continues to increase but is still limited. Thus, three-dimensional (3D) semiconductor memory devices have been developed to overcome the above limitations. 3D semiconductor memory devices may include memory cells three-dimensionally arranged.